Irritable bowel syndrome (IBS), characterized by abdominal pain/discomfort and disturbed[unreadable] bowel frequency, is a common functional bowel disorder that accounts for a substantial proportion of patients[unreadable] seen in primary care and secondary referral centers. The impact on patients' quality of life and the economic[unreadable] burden on the community are considerable. However, the outcome of conventional Western medicine in[unreadable] reating IBS has been disappointing. Several potential new therapeutic agents have been withdrawn[unreadable] because of serious adverse events. Traditional Chinese medicine (TCM) has been used in the treatment of[unreadable] BS for centuries in Asian countries but scientific evaluation of its therapeutic function is scarce. Recently, a[unreadable] a methodologically strong trial of a 20-herb formula showing significant benefit for IBS patients. However, the[unreadable] herbal formulation is inadequately characterized and defined for repeated clinical studies.[unreadable] PROJECT SUMMARY: Subsequent to complete chemical characterization (Botanical Core), we will conduct[unreadable] a randomized, placebo-controlled, double-blind, phase II dose-escalation clinical trial to find an optimally safe[unreadable] and efficacious dosage of this standardized 20-herb preparation in 117 patients aged 18 to 75 with all types[unreadable] of IBS. At each of three dosage levels, 39 participants will be randomized to treatment for 8 weeks with the[unreadable] herbal formula or placebo in a 2:1 allocation ratio, and will be assessed at baseline, weeks 0, 2, 4, 8, and 12[unreadable] for the clinically important and reliable outcome of patient reported global symptom improvement. At the[unreadable] conclusion of the 1st and 2nd dosage levels, safety will be assessed prior to using a higher dosage in a new[unreadable] cohort of participants. We also will assess individual IBS symptoms, nature, severity, duration, and frequencv[unreadable] of adverse events, quality of life, concurrent IBS medications and health care utilization, and will perform[unreadable] blood tests for safety purposes. Adherence to study medication will be verified by pill counts. Results of this[unreadable] dose-ranging study will help to identify the optimal dosage of the herbal formula to be used in future[unreadable] randomized placebo-controlled trials and in head-to-head comparisons with conventional Pharmaceuticals.[unreadable]